My Latest VTOL Twin Electric

[vtolman]

This latest VTOL TWIN ELECTRIC model is based on the previous model (see my other posts) but has a bigger wing cord 235mm x 25mm and wing span 720mm.

The PROPS UP model - has the props as low as possible to the tilt spar tube and proved slightly better than the last model which has the AXI motors mounted on top of the spar tube.

The PROPS DOWN model - is better for hovering, as it has a better crisp pitch response in hover without the slight wobble.
This is due to the thrust center of the props is now lifting from the correct side of the C of G spar tube the motor pivots on.
Example - as the props tilt to move the plane forward, the motors swing backwards behind the C of G. - helping lift the back of the plane up.
It is tricky to make it do this with the props up.

I have just started a LITTLE OSPREY V22 with almost scale proportions and using the same electrical specs as my current models with the fixed props and motors up, but a whole new tilt setup to get the correct thrust and scale appearance.

Kingsley

[MustangAce17]

awesome job VTOLMan,u were the main influence on my project but mine has seen worse for wear(airframes busted) i would love a kit of yours for my electronics

[v22chap]

great job Kingsley ,,, best of luck with this ,,,,, how long until you have pix of the v-22 ??
Larry

[vtolman]

MustangAce can you tell me what results you got for your hover response and gyros etc.

Larry - Nothing worth photos yet - Weeks, months, not sure how long as I get I terribly pre-occupied flying my vtol's.

First the V22 test model needs sorting to confirm my design works as planned, and then improved if needed to some satisfaction. The mass distribution out from C of G for and aft effects the pitch response, and as the size of the model gets too small (or too long also) combined with gyro functions, it can be a tricky match.

The issue is, I prefer to make it look at least stand off scale to some point.
However these models are all limited by the available 10x4.5 counter rotating props which make it a difficult on a small model to perfect for pitch.

It may be a bit like how larger scale model planes fly better than small models.

I am also trying to test CSM gyro features - e.g. heading lock relaxation rates, look ahead gain, direct coupling etc, without any benefits to report so far, but this is a minefield in itself.

I will post a new thread on the LITTLE OSPREY V22 test model as I get results, then I will make the light weight body panels and nacelle, maybe tissue f/glass first up, then vac moulded plastic all going well if it works.

But don't hold your breath on all this !!!!

[v22chap]

The mass distribution out from C of G for and aft effects the pitch response, and as the size of the model gets too small (or too long also) combined with gyro functions, it can be a tricky match.

Tell me about it ,,I have had to go stand off for the same reasons and with cyclic it doesn't make as much difference ,,but I needed 3 " more on the nose to help my bird.


I am also trying to test CSM gyro features - e.g. heading lock relaxation rates, look ahead gain, direct coupling etc, without any benefits to report so far, but this is a minefield in itself.

I will also be good to have some one that knows how the gyro's for this should work find some modern day ones that also work well.
Keep up the good work
Larry

[vtolman]

Larry
I can only take a fying guess at these questions as I have no qualifications, and I am bound to be wrong 9 out of 10 times from past experience.

Mostly I just feel it, or see what it needs as I test fly it.

If the fuselage or mass distribution is too short the gyro/servo pitch response can not keep up with the pitching of the fuselage and is unstable - they may need to match each others speed or reaction time.
I noticed if the fuselage is too short or light the gyro is maxed out and the prop / servo pitching is too late to fix the problem as it will pitch too far too quick.
My little chinook has this slight problem as it has no mass on either side, which is fixed if I strap a 15 inch stick of wood under it sideways to dampen the response time - I dont think it can be perfected with gyro settings or faster servos.
If the mass is too long on the VTOL TWIN the pitch response lags behind developing a slower resonse which can develop into a huge slow wobble.
Heading lock relaxation rate is the amount of heading hold (not gain) control it has, so stick response is conventional but it will hold also.
I could not get over 25% added before it became worse to fly, and it did not feel any better than without it.
For my twin vtol the standard factory settings and non heading hold on the CSM 540 matched the old arcamax gyros very close, and so far I can not improve much on it.
But this is not conclusive as I am very novice with gyros, and need a lot more testing.

With my set ups there are too many variables to test and I need to do one at a time and document it e.g - props up, props down, height of props, exponential, travel adjust, mass dist, different gyros and settings on all concepts mentioned, etc etc. so its a bit like a combination lock. :eek:

Kingsley

[MustangAce17]

vtolman,i will talk about this tomorrow gotta sleep now lol

[Tuner]

I wanted to know if anyone knows of an open source speed controller or a speed controller that you can custom program.

I think it would be very helpfull if we could program a ESC that would better work with these new modern gyros that can run at high speeds 75-150 frames/second. I think getting a ESC to utilize the Engine Govenor techniques you can increase not only the response rate but only its effectiveness.

Or maybe they already will handle the higher frame rates.

Scott

P.S. I thought you might like this link.

http://www.gizmag.com/go/5751/

[RCSuperPowers]

Vtol man... you're a genius head.

[jmolwitz]

Yea ... and a smart face :)

[MustangAce17]

as far as hover on my model i would say the pg-3's held well but i just didnt have the skill to keep it there for very long plus i would almost say my airframe is to short coupled but its actually pretty long but the pitch is kinda touchy,i just got it to fly with both motors tilted 60' and fixed but that only lasted a short while because i tryed to make a quick 180 turn and it stalled since the rudders are not functional but i would say the gyros hold very well

[vtolman]

MustangAce17
I tried some hitec GY130 gyros once on roll and they will never work, and on pitch it took a lot of skill just to keep in a 10 foot square area.
If you have heli experience and can not hover it after trying various gyro gain settings and servo travel adjust then maybe those servos will not work.
I know my setups do require fine tuning with the amount of mix for roll (12%)and a throtle curve (flat curve at mid stick possition) definately helps and exponential on pitch and yaw (40%)
To much servo travel on yaw pitch can make it a hand full also.

[MustangAce17]

after re-reading this i would say i had to much servo(epa)travel on my elevator and the props were to high above the cg to give good stability(i should've realized this before but im a bone head lol)

[v22chap]

(i should've realized this before but im a bone head lol)

Yep you sure are and with me telling you right off the start they were to high.... but that is o.k. because I have been there done that and have the T- shirt :D
I get so involved in the project and how I am going to do it that I fail to see what someone else may be saying on the thread or can't visualize it .

Another good lesson for all ;) :cool:
Keep on trying
Larry

[CarlosTheGreat]

Seen Larry's machine flying on the weekend.
What a Ball tearer.

[Peter W]

vtol man whats happened with this great model of yours? Are you gonna give more details into its construction? I'm sure I saw a plan to kit it somewhere here but can't find it again.
Have you got any other vtol designs to work like edf?

Cheers

Pete

[v22chap]

Peter W
I can answer that for you ,,, he gave the specs for it ,,but didn't want to take the time to draw up plans for it as it was just a plane jane test bed (as he puts it ) ,,but said he would give demensions to someone who would ,,, but we all have our own projects and no time to do it either ,,, Vtolman has moved on to some other great little projects that I am sure he will be showing here soon. I have a great little video of one neater than this one ,,but will not post it until he says or post it himself .Stay tuned .......
Larry

[Peter W]

ok cool just never seen a vtol any where near as stable as this twin rotor design, not only that but awesome reliable transitions and aerobatic capability too! we want more vids!
what would happen with variable pitch too?! inverted vtol hovering?
the holy grail seems to be edf vtol, everyone knows deep down that's just plain cool hehe
I'd like a vtol edf that can also fly at 90+mph and have retracts...

Pete

[Tram]

So, is this thing going to be kitted?

[MustangAce17]

i wonder to,the latest issue of Quiet and Electric Flight has a brief article on Kingsley's VTOL

[MustangAce17]

i will definitely get one if he decides to kit,kingsley are u here?

[Tram]

Sounded like it may get kitted, since it asks what we'd pay for a kit. :)

[semc]

I am planning to build a vtol with to Axi motors (just starting out), has anybody used a gyro to control the motors through a speed controller and does it work, I was also thinking of using a cheep indoor heli tail and gyro to control the pitch on the tail, and possibly rotate this for normal flight, has anybody tried this. If anybody knows of any good websites or links it would be appriciated.

[NZ_Nitro]

he does have another thread on it... http://www.rcgroups.com/forums/showthread.php?p=4582904#post4582904